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This segment was originally broadcast on April 1, 2007. It was updated on July 23, 2007.

If you have ever wondered why the cost of prescription drugs in the United States are the highest in the world or why it's illegal to import cheaper drugs from Canada or Mexico, you need look no further than the pharmaceutical lobby and its influence in Washington, D.C.

According to a report by the Center for Public Integrity, congressmen are outnumbered two to one by lobbyists for an industry that spends roughly $100 million a year in campaign contributions and lobbying expenses to protect its profits.

One reason those profits have exceeded Wall Street expectations is the Medicare prescription drug bill. It was passed more than three-and-a-half years ago, but as 60 Minutes correspondent Steve Kroft reports, its effects are still reverberating through the halls of Congress, providing a window into how the lobby works.

The unorthodox roll call on one of the most expensive bills ever placed before the House of Representatives began in the middle of the night, long after most people in Washington had switched off C-SPAN and gone to sleep.

The only witnesses were congressional staffers, hundreds of lobbyists, and U.S. representatives, like Dan Burton, R-Ind., and Walter Jones, R-N.C.

"The pharmaceutical lobbyists wrote the bill," says Jones. "The bill was over 1,000 pages. And it got to the members of the House that morning, and we voted for it at about 3 a.m. in the morning," remembers Jones.

Why did the vote finally take place at 3 a.m.?

"Well, I think a lot of the shenanigans that were going on that night, they didn't want on national television in primetime," according to Burton.

"I've been in politics for 22 years," says Jones, "and it was the ugliest night I have ever seen in 22 years."

The legislation was the cornerstone of Republican's domestic agenda and would extend limited prescription drugs coverage under Medicare to 41 million Americans, including 13 million who had never been covered before.

At an estimated cost of just under $400 billion over 10 years, it was the largest entitlement program in more than 40 years, and the debate broke down along party lines.

But when it came time to cast ballots, the Republican leadership discovered that a number of key Republican congressmen had defected and joined the Democrats, arguing that the bill was too expensive and a sellout to the drug companies. Burton and Jones were among them.

"They're suppose to have 15 minutes to leave the voting machines open and it was open for almost three hours," Burton explains. "The votes were there to defeat the bill for two hours and 45 minutes and we had leaders going around and gathering around individuals, trying to twist their arms to get them to change their votes."

Jones says the arm-twisting was horrible.

"We had a good friend from Michigan, Nick Smith, and they threatened to work against his son who wanted to run for his seat when he retired," he recalls. "I saw a woman, a member of the House, a lady, crying when they came around her, trying to get her to change her votes. It was ugly."

When the prescription drug bill finally passed shortly before dawn, in the longest roll call in the history of the House of Representatives, much of the credit went to former Congressman Billy Tauzin, R-La., who steered it through the house.

"It's just a messy process," Tauzin says. "I mean, the old adage about if you like sausage or laws, you should not watch either one of them being made is true. It's a messy process."

Tauzin says that the voting machines were open for three hours "because the vote wasn't finished."

As for arms being twisted? "People were being talked to," he says.

And of Walter Jones' comment that it was the "ugliest night" he had "ever seen in politics in 22 years?"

"Well, he's a young member," counters Tauzin with a laugh. "Had he been around for 25 years, he'd have seen some uglier nights."